The present invention relates to a vehicle sun visor apparatus that operates to automatically block incident light that enters a vehicle passenger compartment such as direct sunlight.
In the prior art, sun visor apparatuses are provided above a driver's seat and a front passenger seat of a vehicle to block light that enters the vehicle such as direct sunlight. The sun visor apparatuses prevent incident light from reaching the actual eye positions of the occupants, and prevent the occupants from being dazzled by the incident light. Such sun visor apparatuses are configured to block light of a predetermined area including the actual eye position of the occupant by manipulating a sun visor main body provided in the vehicle. However, in these days, a sun visor apparatus has been proposed that automatically operates in accordance with the actual eye position of the occupant, especially the driver.
Such an automatic sun visor apparatus is disclosed in, for example, Japanese Laid-Open Utility Model Publication No. 5-34013, Japanese Laid-Open Patent Publication No. 2002-331835, and Japanese Laid-Open Patent Publication No. 2003-260933.
The sun visor apparatus disclosed in the publication No. 5-34013 includes a radiation sensor, which detects the amount of radiation of the direct sunlight, a liquid crystal panel located at the upper portion of a windshield of the vehicle in a strip-like form, and a liquid crystal panel control section, which controls the permeability state of the liquid crystal panel in accordance with the output of the radiation sensor. The radiation sensor is located on both sides of the headrest, that is, in the vicinity of the actual eye position. Then, the liquid crystal panel control section determines whether the output of the radiation sensor exceeds a threshold value. If the output of the radiation sensor exceeds the threshold value, the liquid crystal panel is made nonpermeable to block direct sunlight.
The sun visor apparatus disclosed in the publication No. 2002-331835 includes two cameras, a light blocking section, which is located on the windshield and changes the light blocking area for blocking direct sunlight, and a control ECU, which controls operation of the light blocking section. The image of the face of the occupant in the seat is taken by the cameras, and the actual eye position of the occupant is detected in accordance with the shot image of the face. Furthermore, part of the shot image of the face is extracted and the brightness of the extracted image is compared with a predetermined reference value. If the brightness of the extracted image is higher than the reference value, the range of the sun visor is specified in accordance with the detected actual eye position of the occupant to block the direct sunlight that enters the windshield.
The sun visor apparatus disclosed in the publication No. 2003-260933 includes a camera for shooting the face of the occupant and a sun visor main body stored in a storage box. The sun visor apparatus also includes an eye image extracting section, a pupil size detection section, an illumination detection section, a memory, a glare determination section, and the sun visor control section for controlling operation of the sun visor main body. The eye image extracting section extracts the image of the eyes from the face image of the occupant shot by the camera. Then, the pupil size detection section detects the size of the pupils of the extracted eye image, and the illumination detection section detects the illumination of light that shines on the eyes of the occupant from the brightness of the eye image. The memory stores information such as the size of the pupils and the illumination when the occupant does not feel the glare. The glare determination section compares the information stored in the memory with the size of the pupils detected from the eye image and the illumination to determine whether the occupant feels the glare. A glare adjusting section outputs a signal to the sun visor control section based on the determination. The sun visor control section outputs a signal for adjusting the advancement and retraction of the sun visor main body to the storage box. Based on the signal, the sun visor main body advances or retracts from the storage box to block the direct sunlight.
However, since the actual eye position of the occupant when seated differs depending on an individual occupant, it is difficult to detect the actual eye position of the occupant by providing the radiation sensor on the headrest as disclosed in the publication No. 5-34013. The area that actually requires blocking of light extends to the position lower than the actual eye position. Therefore, if it is difficult to estimate the actual eye position of an individual occupant, it is difficult to perform the light blocking control in accordance with the eye position of the occupant.
Furthermore, the sun visor apparatuses disclosed in the publication No. 2002-331835 and the publication No. 2003-260933 require various configurations such as cameras. Therefore, the sun visor apparatuses undesirably become complicated and expensive.
Accordingly, it is an objective of the present invention to provide a simple vehicle sun visor apparatus that easily estimates an eye position of an occupant and performs an appropriate light blocking control using the estimated eye position.